javascript map

JavaScript
array.map((item) => {
  return item * 2
} // an example that will map through a a list of items and return a new array with the item multiplied by 2const myArray = ['Sam', 'Alice', 'Nick', 'Matt'];

// Appends text to each element of the array
const newArray = myArray.map(name => {
	return 'My name is ' + name; 
});
console.log(newArray); // ['My name is Sam', 'My Name is Alice', ...]

// Appends the index of each element with it's value
const anotherArray = myArray.map((value, index) => index + ": " + value);
console.log(anotherArray); // ['0: Sam', '1: Alice', '2: Nick', ...]

// Starting array is unchanged
console.log(myArray); // ['Sam', 'Alice', 'Nick', 'Matt']// The map() method creates a new array populated with the 
// results of calling a provided function on every element
// in the calling array.
const array1 = [1, 4, 9, 16];

// pass a function to map
const map1 = array1.map(x => x * 2);

console.log(map1);
// expected output: Array [2, 8, 18, 32]const numbers = [0,1,2,3];

console.log(numbers.map((number) => {
  return number;
}));function listFruits() {
  let fruits = ["apple", "cherry", "pear"]
  
  fruits.map((fruit, index) => {
    console.log(index, fruit)
  })
}

listFruits()

// https://jsfiddle.net/tmoreland/16qfpkgb/3/array.map( item => item.id )

array2.map( item => item.toString() )

array2.map( item => item * 3 )

// this will apply a transformation to all elements of an array
// "" item => something "" is the transformation (function)The map() method creates a new array with the results of calling a provided function on every element in the calling array.// make new array from edited items of another array
var newArray = unchangedArray.map(function(item, index){
  return item;	// do something to returned item
});

// same in ES6 style (IE not supported)
var newArray = unchangedArray.map((item, index) => item);
Source

Also in JavaScript: